Question

Identify oxidant and reductant in the following redox reactions.

${Hg}^{2+}+{NO}_2^{-}+H_{2}O⟶Hg+{NO}_3^{-}+2H^{+}$

• A. Oxidant: ${Hg}^{2+}$ ; Reductant: ${NO}_2^{-}$
• B. Oxidant: ${NO}^{2-}$ ; Reductant: ${NO}_3^{-}$
• C. Oxidant: ${Hg}^{2+}$ ; Reductant: ${NO}_3^{-}$
• D. None of these

Answer 1

The correct option is A Oxidant: ${Hg}^{2+}$ ; Reductant: ${NO}_2^{-}$

The balanced redox reaction is as follows:
${Hg}^{2+}+{NO}_2^{-}+H_{2}O⟶Hg+{NO}_3^{-}+2H^{+}$

The oxidation number of mercury changes from +2 to 0. Thus mercury is reduced.

The oxidant is $H{g}^{2+}$.

The oxidation number of N changes from +3 to +5. Thus, N is oxidized.
The reductant is $N{O}_2^{-}$.